Blackbourne
by Otterpop96
Summary: Based on the premise of Black Bullet, an apocalyptic virus has spread across the world, leaving the human race in shambles. Brother-sister pair Kira and Tsuro fight these creatures, Parasites, in Japan, and begin to lose hope...until the arrival of American twins Ali and Marissa, who show that everyone has their hopes...and their secrets.
1. Parasite

The black wastelands cut through the world. Charred remains remained. A teenage girl stepped out into the world, careful of any movement around her. She looked around. Everything was dark and black. But that was how it had been for the past few decades. Everyone knew.

The girl sat down on an ash-covered rock, sighing with her mouth closed. It was almost nine years ago, nine years ago that she had lost everything: her house, her friends, even her family….

"Kira?"

The girl turned around. A boy stood there, taller than her, with short blonde hair, and a neutral expression.

"Kira, we should probably head back," he told her.

The girl nodded her head. "Yeah, you're right." She walked towards the boy, casually walking through the darkened earth, a black sky above them. They walked and walked until they reached a large and wide hill, holding a massive steel door. The two teenagers approached the door.

"Halt!"

Kira and the teen boy halted and slowly turned her heads. A man, clothed in heavy military uniform, approached them at gunpoint.

"No one is allowed here," the guard warned forcefully. "Reveal your ID's!"

The teenage girl sighed. She cleared her throat and began to speak.

"ID Number 47496. Kira Hironaka. Age 17. Hokkaido Iron Sickle Specialist, Class J."

The soldier then looked at the boy, who cleared his throat, somewhat nervously, and spoke as well.

"ID Number 47497. Tsuro Hironaka. Age 14. Hokkaido Sniper Class J."

The soldier, still staring at the two of them, took a hand off his gun and reached for his back pocket, pulling out a device. The girl, Kira, leaned her head slightly forward to see him inputting information into the device, numbers it looked like, and moments later he relaxed and set the device back into his back pocket.

"Sorry," he apologized. "You check through."

The boy, Tsuro, blinked. "You must be new here, huh?" he said, his tone slightly challenging. "You _really_ don't need to-"

"Need to worry about a thing," Kira interrupted immediately, smiling. "We're clean."

The soldier looked back and forth between Tsuro and Kira before shrugging his shoulders and walking towards the door. He opened it with great muscle strength, and Tsuro and Kira walked through. They entered into a metallic hallway, and walked for what felt like a hundred yards until they came into a large room, leading to another large metal door. Two guards stood watch, though neither held guns as the first ones did. They nodded their heads as Tsuro and Kira approached, and input some numbers and codes into the door before opening them.

Kira walked into a massive iron chamber, where many guards walked around, each carrying guns. Kira sighed as she walked, addressing fellow soldiers as she went along. Two soldiers went up to the two teenagers, laughing and grinning.

"Kira! Tsuro! What's up?" one of the soldiers, a younger man with dark facial hair, asked cheerily. "How's our favorite teenage sibling duo?"

Tsuro shrugged his shoulders, smiling ever so slightly. "Not bad, Officer Hado. Just doing our rounds."

"And by rounds," Kira sighed. "You mean only walking within sight of the entrance."

"Hey, it's better than nothing," the other soldier, older than the first and with lighter hair, commented. "The two of you are incredible allies to fight alongside, you know."

Kira nodded her head. Then, smiling, asked sarcastically, "What would you do without us?" She walked away without another word, grumbling to herself.

"Yeah, well, those damn bastards out there hardly stand a chance against us," Officer Hado sighed as Kira walked away.

"It sucks to fight some of them," Tsuro complained. "They're so strong sometimes."

The soldiers nodded their heads. "Could never agree more," the older soldier sighed. "Would you guys like something to eat?"

"Definitely," Tsuro replied. "Kira, you want some food?"

Kira stopped and turned around, grumbling to herself. Then her stomach grumbled. Tsuro chuckled.

"Looks like someone _is_ hungry after all," he joked.

Kira, smiling, rolled her eyes and walked over to her brother, nudging him in the arm. "All right, you can shut up now."

Tsuro shrugged, smiling, as he and Kira walked with the two soldiers towards an area where scents wafted in the air. Kira breathed in. She smelled rice without a doubt, and perhaps fish too. The four of them approached a counter where some burly men stood, catering and dealing with trays upon trays of food.

"Chef," Tsuro called out. "Mind giving us some rice bowls?"

One of the burly men turned around, a blank expression on his face. Then a scowl appeared and he grumbled, turning back around. Kira gulped slightly, but then the same man turned back with four bowls of rice in his hands, and he set them down hard on the counter in front of them. Kira and Tsuro quickly took the rice bowls, as did the soldiers behind them, and walked off.

"Kira! Tsuro!"

The siblings turned around to see another chef, much skinnier than the others, gesturing for them to come over. He looked very friendly and happy to be there.

Kira, with Tsuro at her side, walked over to the chef, watching as he smiled. When they neared him, he whispered loudly, "How about taking some red snapper with you? I'm sure you'll like it."

Kira blinked. "Red snapper, huh?" she asked casually. "Never had that. Sure, why not?" She held out her bowl of rice.

The skinny chef reached down and grabbed a ladle that he used to scoop up bits and pieces of what looked like cooked red fish before drizzling just a little over Kira and Tsuro's rice bowls. Kira sniffed in. The fish had quite a nice scent. The chef even added some soy sauce to add to the bowls of rice.

Kira and Tsuro walked away from the chef, feeling more delighted than they were earlier, and went to sit down at an older metal table. The two soldiers followed suite, and the four of them sat down calmly at the table, eating their meal quite peacefully. The food did not taste all that good, but Kira had tasted worse. And this could probably be some of the best food anyone could ask for.

"Got any new bastards you have taken out?" one of the soldiers asked with a laugh.

"I wish," Tsuro replied just as cheerily. "Nah, we didn't see any today."

"Let's hope we don't," Kira pointed out.

Tsuro turned to her sister, surprised at her remark. "Why do ya say that?" he inquired.

Kira sighed and set down her eating utensils. "The more of them are out there, the greater the chance those things can infect more and more of us until the human race is all but extinct. If anything, it's a good sign there _aren't_ any of those out there."

"But," Tsuro reminded. "If there are, we will be there to stop them, right?"

Kira nodded her head. "Of course," she replied, smiling faintly. "You can always take them down with your sniper, and I always got my kusarigama."

"Or your chigiriki," Tsuro added.

"I'm much more fond of my kusarigama," Kira corrected.

"Just what exactly are those weapons?" the second soldier questioned in confusion.

Tsuro blinked, staring at the soldiers. "Well, a sniper is-"

"Idiot, _everyone_ knows what a sniper is," Kira sighed in disbelief. "They mean my weapons. I won't take them out, but a kusarigama is a chain sickle, specifically a strong iron chain sickle. A chigiriki is my secondary weapon choice. It's an iron staff with a strong and durable retractable chain. A spiked iron ball is attached to the end of the chain."

"I can see why that's your secondary weapon," one of the soldiers commented. "Sounds like some kind of old-fashioned Medieval Age weapon."

"Well, I cannot shoot a gun worth shit," Kira groaned. "So being a gunman doesn't do it for me."

"Wish you had your brother's talents, eh?" the second soldier teased.

"Wishes," Tsuro repeated. Kira punched him hard in the shoulder. Tsuro just stuck out his tongue back at his sister.

"Anyways, I prefer hand-to-hand combat style rather than distance combat like my brother," Kira added. "It means I have a much greater chance of getting infected, but so far so good."

"You've only been using your weapons for four years or so," Tsuro put in.

"You've been using guns for longer," Kira said. "Twice as long, I think. Eight years? Maybe nine?"

"Lost track, I guess," Tsuro said with a sigh.

'You two are some pretty big fighters though, huh?" the first soldier asked. "I mean, you're pretty well known around here. And you're only teenagers."

"We're some of the best of the best!" Tsuro cheered.

Kira grabbed her brother by his ear lobe and pulled. Tsuro snapped and then groaned. She shook her head in disapproval. "Honestly, you think much too highly of yourself sometimes, don't you?"

A radio nearby crackled. "Attention units, attention units."

Kira blinked and immediately reached down for her radio on her belt. She pressed a button the side. "Units forty-nine and fifty on standby," she said seriously.

"We have a situation," a staticy voice on the other end of the radio said, sounding somewhat masculine. "Code One on east side."

Kira looked over at Tsuro, who nodded his head. "Sounds like there's trouble."

"Right," Kira agreed, standing up quickly. "Get your weapon. We're heading out."

In an instant, Tsuro reached into his boots, each as tall as his knees, and pulled out something long from each of his boots. They appeared to be pieces of something. Tsuro quickly put them together and twisted them until they locked tight into place. After that Tsuro clicked and pulled, until the two pieces turned completely into a long and powerful-looking sniper rifle.

"Amazing!" the second soldier called out.

"Fine then." Kira quickly reached around for her back and pulled out a chain sickle, whipping it out as though she would use it right then and there.

"East side, right?" Tsuro inquired, his tone serious for the first time.

"Let's go," Kira said. The two of them raced off in moments, heading for the eastern side of the Hokkaido base. Even with no sun to tell them direction, Kira and Tsuro still knew where to head off to.

By the time Kira and Tsuro had reached the eastern side of the base, they quickly exited through a large metal door, ran through a long dark hallway, and reached a door that when it opened it led to the outside world.

"Ashes and darkness once again," Tsuro sighed quietly. "Man, I would give anything to see green again."

"You've never seen green before, smart one," Kira sighed.

"Sure I have!" Tsuro snapped. "On TV and movies!"

"That does not count," Kira grumbled. "And keep your voice down."

Tsuro shut his voice off and walked forward, keeping by Kira's side while looking around cautiously. Kira made absolutely certain to do the same. She looked around, listening intently for anything suspicious.

"Hold up," Tsuro said, putting an arm in front of Kira's face. Kira grumbled, glaring at Tsuro. He merely gulped and looked away.

"Sorry," he apologized nervously. "Go on ahead."

Kira moved Tsuro's arm aside and moved ahead slowly and carefully. Suddenly, she heard something. Something out of the ordinary. A strange rustling noise. It seemed to be coming from behind a large rock ahead of them.

"Careful," she warned her brother, turning to look at him. Her eyes suddenly widened in disbelief as she realized that Tsuro no longer stood by her side. She twisted her head quickly to see Tsuro right behind the rock already, carefully looking over the other side of the boulder. Kira grumbled and raced ahead quietly, going next to her brother's side. Then she, too, gazed upon the other side of the rock. Her eyes furrowed immediately.

Strange movement caught her attention immediately. Slow and sluggish, and completely uncoordinated. Kira's eyes became squinted as she realized that the figures that walked a ways in front of her looked quite human.

"Take the south side and draw their attention," she whispered to her brother. "I'll come 'round on the north side."

"Careful out there," Tsuro told her. Kira nodded and took off to the left immediately, keeping as quiet as she possibly could, running as though following the edge of a huge circle. She kept her body crouched the entire way, and finally stopped, sitting up against an ash-covered rock with her back facing the human-like figures. She slowly lifted her head and looked up over the rock. Six human figures groaned and walked around sluggishly. Kira breathed out slowly.

_Six, huh?_ she thought to herself. _Not as many as I thought, but these things _must _be taken care of before they advance to the next stage._ Kira stared over the rock, noticing movement on the other side of the dark and flat clearing. She recognized her brother instantly.

Kira carefully held up her fingers, three on each hand, and made certain to show them to the other side of the clearing, before ducking down to her hiding place once again. A few seconds later, a pop went off. Then a second, and then four more, before all fell silent. Kira smiled, poking her head up.

All six of the figures sluggishly began walking towards the other end of the clearing, where Kira knew Tsuro was hiding. She clutched her kusarigama tight and revealed herself from her hiding spot, bolting for the six figures as quietly as she could. She carefully waved back and forth, watching as the six figures kept heading in Tsuro's direction. The chain clinked. One of the figures slowly turned to face Kira.

_Shit!_ Kira lunged forward in an instant as soon as the human figure did, swiftly using speed and strength to cut off its head clean from its body. The figure screeched horribly as it was decapitated. Dark blood splattered up from its severed neck and it fell to the ground.

In an instant many shots rang out, hitting each of the other five sluggish figures. Kira watched as many of them fell, but then got back up, merely dazed and unable to function as they had before. Kira immediately took her chance and shot forward, slicing left and right with precise ease. She stopped, and instantly all five of their heads were sliced clean off their bodies. Many of them had their arms, legs, or chests sliced open also. They all fell dead to the ground, unmoving.

"You scuffled," a voice called out to her.

"Shut up, Tsuro-kun!" Kira shouted. "It was most certainly _not_ on purpose! Wait, why am I even saying that?! I did not scuffle at all!"

"Oh, really?" Tsuro challenged as he approached his sister. "Then why in the hell did it turn towards you?"

"I don't know," Kira snapped in return. "Maybe something else caught its eye and then it caught sight of me. Who knows why in the hell Parasites do what they do!"

"Still, you should really be more careful."

"Oh, like you are one to talk." Kira punched her brother hard in the shoulder. He whined a moment before she continued. "You act like you're all big and the greatest tough guy in the world, but come on. You are much more of a lousy fighter when it comes to hand-to-hand combat. You do not _really_ do the fighting; just creating the diversion."

"Yeah, well, that's how I was taught!" Tsuro argued, looking as though he wanted to debate the issue, though not seriously.

"Let's just get back," Kira sighed, her kusarigama in hand. "We must report this."

"So formal," Tsuro teased.

"Just be glad that these Parasites were Stage 1," Kira sighed. "A hell of a lot easier to deal with….."


	2. In the Beginning

"Wax?" Kira asked.

"Check," Tsuro answered.

"Oil and fuel?"

"Check."

"Non-perishables?"

"Check again."

"Did the ammunition make it in?"

"Ammo is a big fat check."

"Don't call it ammo," Kira grumbled.

"Why?" her brother challenged.

"That is probably the most stupid shortened word in the world."

"What's your problem with me calling it ammo? It's just a word."

"Can you _not_ act like a child for once?" Kira demanded, smacking the pencil in her right hand to the clipboard in her right. "I mean, really? We're adults in this situation right now."

"Situation?" Tsuro challenged. "It's a routine inventory check. We do these, like, _twice a day_!"

"Stop complaining," Kira told him simply, focusing on the papers on her clipboard. Tsuro snorted and the two of them continued.

"Paper and writing utensils?"

"Check," Tsuro answered with a sigh. "Low on pencils."

"_Supply of pencils_ is low." Kira looked up and glared at her brother. "Were you born yesterday? Stop saying everything incorrectly. Besides, pencils are not the _only_ writing utensils we use; we also use pens, and sometimes highlighters-"

"Alright, alright!" Tsuro groaned loudly. "Stop being such a smart ass! And a total Grammar Nazi!"

Kira stared at her brother a few moments more before, in an instant, smacking him hard on the head with her clipboard. Tsuro fell to the floor, whining while holding his head tight with his hands. It felt sore instantly.

"Let's continue," Kira said, as though nothing had happened.

Tsuro whined. _Why does my sister have to be a complete _bitch _sometimes?!_ he thought to himself. He slowly began to stand, his head still sore but not as much as seconds before.

"Scrap metal?"

"Yeah," Tsuro replied quietly, still rubbing his head. "_Plenty_ of that."

"I'll check it off as excess," Kira said flatly. "Leather?"

"I hardly see any of that."

"Leather is getting harder to find lately, but maybe the Commander can do something about it. What about frozen meat?"

"I checked that this morning, and we had enough for a few weeks for everyone here."

"We might need some more, just to be safe. What about-?"

Kira's question was cut short as loud voices echoed around them. High-pitched and quite whiny. Tsuro turned his head curiously. A group of children walked by. Five of them it looked like, two girls and three boys. Though all different ages clearly, the oldest to Tsuro looked to be about ten years old. All of them whined loudly.

"I'm hungry," one of the girls chirped.

"I want to eat better food," one of the boys grumbled loudly.

"I want to go outside!" the second girl cried.

"I want to go home," a second boy piped up. "Why can't we go _home_? I hate this place!"

"It's all stuffy in here," a third boy whined. "Why can't we leave?"

Tsuro sighed, thinking nothing of the conversation. "Come on," he said, talking to his sister. "Let's just-" Tsuro halted as he realized Kira stared at the little children with a strange expression on her face. Tsuro's eyes widened. "Kira-senapi, hold on just a-"

Kira ignored her brother and walked forward, towards the young children, not even thinking about the clipboard she held. She stalked up to the children, stopping them in their path.

"Excuse us," the first little girl said patiently.

"Sorry about that," Kira apologized. A smile quickly emerged on her face, something Tsuro rarely saw. "I just happened to overhear your conversation just then."

"Yeah," the second boy mumbled. "We wish we could go home."

"You _do_ know that, for now, this is your home, right?" Kira reminded.

"We see a lot of people in better homes!" the third boy argued. "Ones with grass and bright sunlight! We _hate_ it in here!"

"It's dangerous out there," Kira told them.

"How?" the second girl inquired curiously and doubtfully at the same time. "What's out there?"

Kira knelt down to the kids' eye level. "Well, you kids like stories, right?"

All five kids beamed up. "Yeah!" the second boy cheered. "What kind of story is it?"

Kira shook her head, leading the kids to acquire gazes of puzzlement.

"Sorry, but I'm afraid this kind of story is not a happy one," Kira told them. "It's about why we have to stay in this bad place. It's about what's out there."

"What _is_ out there?!" the first girl whined. "Why won't anybody _tell_ us?!"

"For good reasons," Kira sighed. "I would say it started a long time ago…..of course, it started thirty-two years ago."

"Thirty-two years?" the second boy asked, awestruck. "Wow, that's a long time. That's older than my mom and dad!"

"Thirty-two years ago is when it happened," Kira continued. "Life used to be normal. It was peaceful. But then something terrible happened. The weather changed. Strange things began appearing."

"What _kinds_ of strange things?" the first girl asked, her tone full of desperation as though she wanted to know very badly.

"You kids certain you want to know?" Kira asked. All the kids nodded their heads.

"Alright. Strange things? What I mean is that a bad virus appeared."

"What's that?" the third boy, clearly the youngest of the group, asked.

"A virus is like a really bad flu bug," Kira answered simply. "A disease."

Tsuro noticed that all the kids flinched as Kira uttered the d-word. Perhaps young, but just the word itself sounded evil. He could relate.

"A disease?" the second girl asked, her voice shaking.

"A terrible disease," Kira confirmed. "It created an outbreak, something that spreads like crazy. And it spread to all over the world."

"What did this outbreak thing do?" the first boy asked, sounding more curious than terrified.

"It spread," Kira answered, her tone becoming much more grim. "The world became dark. And the way it affected…..sorry, the way it _infected_ people, was crazy and unbelievable. People weren't even people anymore. They had become something infected, something almost undead it sometimes felt like. They became creatures we now call Parasites."

"Just the word 'parasite' make me feel sick," the second girl groaned, a look of disgust and unease on her face.

"What kinds of Parasites are they?" the first boy asked.

"Parasites are Parasites," Kira told them. "They're all kinda the same. But there are different stages of Parasites, which tells us how long they have been infected."

"Stages?" the first girl asked curiously, looking up. "I heard 'bout that somewhere….."

"Stage 1 are simple Parasites," Kira explained. "Human-zombie-like creatures. Stage 2 are the same, but have animal or fungal features, too. They're faster than any other Parasites."

"What's fungal?" the third boy asked.

"Think of something like mushrooms, but really deadly," Kira answered. The kids looked at one another in disbelief.

"Stage 3 Parasites come next," Kira continued. "They don't look like people anymore, but really disgusting creatures like animal-fungus combinations. They're seen as the strongest of all the stages."

"Are the super strong?" the second girl asked.

Kira nodded her head. "Very. And they're considered really deadly, too. The Stage 4's are next. Stage 4 Parasites are when they start to grow really big. Like animal-animal combinations, or sometimes even human-animal combinations."

"What about fungal-thing-like?" the second boy asked.

Kira nodded her head. "Sometimes. But despite their bigger sizes, most Stage 4 Parasites are very agile and nimble."

"What's that mean?" the third boy inquired.

"Think of it like this," Kira answered, holding up a finger as though explaining. "Agile is like being quick and able to dodge stuff really good and getting around obstacles really fast."

The kids looked at one another, unable to comprehend what Kira told them.

"The Stage 5 are the last of the Parasites," Kira then said. "And they're probably the worst and most dangerous of all of them. Stage 5 Parasites are _huge_."

"How huge?" the first boy asked doubtfully.

"Sometimes almost elephant huge," Kira answered before stopping herself. "Or, let's try something you guys know." Kira thought to herself a moment. "Think of something as big as a Yamoto truck. And much bigger."

The kids all widened their eyes in disbelief. Tsuro breathed out of his nose. Kira sure knew how to estimate well.

"Does that mean everyone's gonna turn into Parasities?" the second boy asked frightfully.

Kira shook her head, smiled, and rubbed the little boy's head calmly. "Oh, of course not," she answered. "That's what my brother and I are here for."

"What do you do?" the first girl asked.

"Tsuro-kun and I fight these Parasites and get rid of them," Kira replied. "Once all of them are gone, we can go back outside."

"Woah….." the first boy breathed in a small voice.

"You and your broder do _all_ that work?" the third boy asked, his expression awestruck.

Kira laughed. "Oh, it's not just us!" she said with a laugh. "There are all _kinds_ of men and soldiers fighting the Parasites to get rid of them. I know it seems like a long while, but just you wait! We will get rid of them soon."

The five kids all looked at one another, excitement clearly bubbling among them. They soon walked away, waving to Kira delightfully.

"Bye, miss!" one of the boys called out, before all five of them disappeared behind a corner.

Tsuro approached his older sister, snorting. "All right, when will you get rid of that fake smile?"

Kira faced her brother and frowned immediately. "How did you guess?" she inquired.

"Please," he sighed. "I've known you my entire life. I know when you're faking it and when you're not. Besides, you have not shown any actual smile in years."

"Seven years ago…..." Kira sighed. "Nevermind that, let's just continue with our work."

"Let's take a break," Tsuro suggested. "I'm sure you need it. You look tired from all that pretending."

Kira glared at her brother. Tsuro shrugged his shoulders as his sister walked away. Tsuro looked in another direction, thinking to himself. _That's right,_ he thought. _The last time…...was seven years ago…_

His mind brought him back to a time where he was young, seven years old, actually. Kira was about to turn eleven, something she said she had looked forward to for a long time.

_Why is eleven such an important age for you, Kira-chan?_

_Well, 'cause it's the first time my age is two of the same numbers!_

_You're weird, Nee-san._

_Tsuro-kun, don't be mean to your sister like that._

_Yeah, Nii-chan._

_Kira-chan, now _you're _being disrespectful._

_I'm home!_

_Papa! You're back!_

_We were worried about you, Papa!_

_No need to worry about me, I'm fi-_

…

_Kira-chan! Tsuro-chan! Get back!_

_Mom!_

_Hide yourselves, now! Kira-chan, get your brother somewhere safe!_

_Right!_

_No, Momma! Papa!_

_Nee-san, let me go!_

_Get back or you'll get killed!_

_No! We can't leave Momma and Papa behind! We can't…..!_

Tsuro flinched at the voices in his head.

"Tsuro-kun, you okay?"

Tsuro switched back to reality as his sister addressed him. He turned to look at her, and her expression appeared concerned.

"Yeah, sorry," he apologized with a weak chuckle.

"I know that look," Kira said simply. "You don't fool my eyes. I know it still hurts, but we have to move on."

Tsuro sighed. "Yeah, I know, you're right. Anyways, want to continue checking supplies?"

Kira smiled slightly and nodded her head. "Of course we can," she replied, focusing her attention back on the clipboard. "Where did we leave off? Lighters?"


End file.
